Rath M, Pagenstecher A, Hoischen A, Felbor U.
Postzygotic mosaicism in cerebral cavernous malformation.
J Med Genet 2019;
57:212-216. [PMID:
31446422 PMCID:
PMC7042965 DOI:
10.1136/jmedgenet-2019-106182]
[Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 01/02/2023]
Abstract
Background
Cerebral cavernous malformations (CCMs) can cause severe neurological morbidity but our understanding of the mechanisms that drive CCM formation and growth is still incomplete. Recent experimental data suggest that dysfunctional CCM3-deficient endothelial cell clones form cavernous lesions in conjunction with normal endothelial cells.
Objective
In this study, we addressed the question whether endothelial cell mosaicism can be found in human cavernous tissue of CCM1 germline mutation carriers.
Methods and results
Bringing together single-molecule molecular inversion probes in an ultra-sensitive sequencing approach with immunostaining to visualise the lack of CCM1 protein at single cell resolution, we identified a novel late postzygotic CCM1 loss-of-function variant in the cavernous tissue of a de novo CCM1 germline mutation carrier. The extended unilateral CCM had been located in the right central sulcus causing progressive proximal paresis of the left arm at the age of 15 years. Immunohistochemical analyses revealed that individual caverns are lined by both heterozygous (CCM1+/−) and compound heterozygous (CCM1−/−) endothelial cells.
Conclusion
We here demonstrate endothelial cell mosaicism within single caverns of human CCM tissue. In line with recent in vitro data on CCM1-deficient endothelial cells, our results provide further evidence for clonal evolution in human CCM1 pathogenesis.
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